Rotary steam drier



Aug. 18, 1953 v G. ENGSTROM l ROTARY STEAM DRI 2 Sheets-Sheet .1

Filed Feb. 12. 1952 Aug. 18, 1953 G, ENGSTROM 2,648,914

ROTARY STEAM DRIER Filed Feb. 12, 1952 2 sheets-sheet 2 INVENTOR Patented Aug. 18, 1953 ROTARY STEAM DRIER Gustav Engstrom, East McKeespoi-t, Pa.; Fanny M. Engstrom administratrix of said Gustav Engstrom, deceased Application February 12, 1952, Serial No. 271,111

This invention relates to steam driers and particularly to an improvementI therein by means of which condensed moisture can be readily removed from the interior thereof. Rotary steam driers are used in numerous applications where rapid drying of a lrn of material is desired. For instance, in the paper industry rotary driers are used to dry the paper web leaving the papermaking machine. Likewise, many comminuted materials such as synthetic resins, plastics, cement, sand, gravel or other such materials may be passed over or through a rotary drier to remove moisture or other volatile components. In any such application large quantities of steam are required to pass into the drier to maintain the drying surface at a suiliciently high temperature to eiectively dry the web in contact with the surface of the drier. The exchange of heat from the steam inside the drier to the lm of material on the walls of the drier results in the condensation of considerable amounts of steam into Water, which water collects in the bottom of the rotating drier and tends to hang on the walls of the drier as it rotates. This collected moisture is undesirable because it tends to cool the portion of the drier with which it is in contact to a temperature below the temperature of thesteam and results in increased condensation and decreased drying elciencies of the drier; Since the driers of this type are rotated abouta` horizontal axis it is impossible to remove this condensed water excepting through the axis of the drum. This situation creates the problem of elevating the condensed water from its position at the bottom of the rotating drier to the level of the axis of the drier in order to remove it from the interior of the drum. Many devices have heretofore been proposed for accomplishing the'removal of this condensed water from the interior of the rotating drier. These proposed devices have not been entirely satisfactory for many reasons, Generally, they have depended upon the auger principle and have attempted to carry the steam and water from one end to the other of the drum in a series of channels which spiral along the interior of the drier. Such devices carry whatever condensed water is formed along the surface of the drier in the channel and tend to spread it over a greater area than would be the case if it were simply permitted to fall to the bottom of the drum. 'Ihus while carrying the water out of the drum they actually give it a greater contact with certain portions of the drum surface than wold be the case with an equal quantity of water on the bottom of the drum in the ordinary fashion.

7 Claims. (Cl. :i4-124) I provide a rotary steam drier in which these diiculties of the prior art driers are avoided. I provide a rotatable drier comprising generally a drying surface, means for introducing a heated fluid medium in heat exchange relationship with said drying surface, means collecting cooled fluid resulting from removing the heat from the heated fluid medium, means for periodically removing a portion of the cooled medium and carrying it along a conical helicoidal path to a point-on the axis of rotation of the drier and means carrying the cooled medium from said point to discharge it out of the drier. I preferably use steam as the heated fluid medium.

I provide a rotary steam drier having preferably a single hollow outer steam chamber or in larger sizes, a single hollow chamber surrounding the periphery of the drum formed by an internal drum of smaller diameter. This permits the use of smaller quantities of steam at higher velocity within the interior of the drum than in the case of a single large drum. One end of the drier is cone-shaped, the apex of the cone opening Vinto a discharge pipe on the axis of theA drier,` an internal cone is provided the walls of which'are substantially parallel to the outer cone, said inner cone being spaced apart from the outer cone by an annular ring connecting the periphery of the base of the inner cone with the base of the outer cone thereby'forming a hollow conical chamber in the end of the drier. Two spaced-apart openings are preferably provided from the interior of the drier into the interior of the conical chamber'.

Means are provided within the hollow conical chamber to carry the water entering the open- .ings from the interior of the drier along the surface of the cone to discharge at the apex of the cone as the drier is rotated. The means for carrying the water to the apex of the cone is preferably in the form of an outer baille or vguideway made up of at least three conical helicoidal flights, and an internal baille or ilight intermediate the two openings and within the boundaries of the outer baille. The outer baffle is preferably made up of a conical helicoidal flight beginning at a point adjacent to and leading the'rst of two openings to enter the condensed water when the drum is rotated and terminating at a point adjacent the apex of the cone where it'joins with the second member of the outerbaie. The second member is developed from two conical helicoids which intersect intermediate the distance from the base of the cone to the apexto form a water-retaining pocket. v This second member begins at a point spaced from and trailing the last of the openings to enter the condensed Water and joins the iirst member enclosing the apex of the cone within the outer baille. The internal battle is in the form of a partial helicoid beginning at a point adjacent to and in front of the last opening to enter the condensed water and terminates at a point intermediate the first and` second; members of the-outer baffle and adjacent' the point where the two helicoids ofthe second member join to form a water-retaining pocket.

I have not attempted to explain oi; detail all. of the novel features of my invention but have simply drawn attention to particularfeaturesand. have outlined the advantages thereof. details, objects and advantages of the invention will become apparent as the followingdeseripf.- tion of a present preferred embodiment thereof proceeds. I

In the accompanying drawings I have shown a present preferred form. or apparatus embodyingv the features of my invention and: several modifications thereof1 in which Figure 1 is a: vertic'al'section of adrien accord.- ingto` my. invention;

Figure'Zis a perspectiveviewofthe condensate removing i'ghtsand: the inner' cone ofv a drier according to. my invention;

Figure 3 isf a modified former my invention particularlyl adapted? forsmaller. dryingrolls;

Figure 4l is: another modiiedl form ot my inventionf;

Figure-5 is a form' of: myinventionparticularly adapted for drying comminuted or' finely divided materiali Referring' more. particularly tcr the drawings there is provided' anv outer cylindrical shelll I9 andI an'. innerf cylindrical shellVv II spaced apart therefrom. An inner cone I2.y attached to one 'end' of the inner shell II: forma with. an" outer cone I'3` connected: to one. end: off the outer. cone a passage for delivering steam entering the' initerior of the' outer. coneY I3: through: an inlet pipe; I4' through the center ofthe axis'ofr rota'- tion.. The inlet'. pipe Ii'4 passes throughv the inter-lor; of' a: supporting shaft carrying the drier in thefusualmanner-and is connected to a source of 'steam by welt-known meanswhich itisrdeemed unnecessary tof describe;

The opposite-end Vof' the outer shell; Idl'i's corrne'cted to` an. outer cone Iziy and. the? innen shell to an inner cone. I6f. The spacer.A between. the inner cone Ifand'outerfcone t5 is closedioi from thef spaceA between.Y inner shell; I'I andI the outer shally Iii-byan. annular: ring' I'If. Aa pair of IB; andi I9rspaced apart. fronteach. other in. this annular ring' IIf' communicate; frcrnf the spracezy betweencones I5-y and' I to the space-beftweenshells III and I'I. An outlet pipe 201s" con;- n'ecte'dx to the; apexfof. the-outer cone I5 for res moving water; steam' or other condensate from betweenv the' cones I5v and |62 This outlet pi'pe 21llike1inlet` pipe I 4 passes through a supporting sha-tt' and is connected: to a drain pipeV inY well'- recognized manner.

A. conical helicoidalslight 2I begins. at'. a point adjacent. to and' leading the opening-1 I8 which rstenters theliquid toA be removed as the drier'rotates. This flightZI' terminates adjacent the apex of:` the: cone conformed bythe inner shelL I6. A second night 22, madeY up of two conical heliccids which; are brought together intermediate-.their endstoiform a welly 23; begins adjacent tow anclfollowingf the. last opening; I9 to enter. the. liquid. to be removed; as the drier Other d rotates and connects with the flight 2| at its terminus adjacent the apex of the cone. These two flights 2| and 22 are welded or otherwise fixed to the inner cone I6 and the outer cone I5 to form an internal guideway carrying condensate from the openings I8 and I9 and discharging it through the pipe 2|.'Il` at theapex of the;v conical end. I5. Ani intermediate flight 24, also of'v conical helicoidal shape, is placed intermediate the leading flight 2| and the trailing or following flight 22 beginning at a point on the annular. ning I'I between the openings IB and I9' and terminating at a point spaced from the apex! of' the-inner cone I6. This intermediate night 2'45 carries condensate entering the space between` the inner cone I6 and outer cone I5 Hthroughcthe:opening I8 to a point spaced from the apex of the inner cone I6 when the condensate is discharged into the well 23 in the trailing night 22. This intermediate flight 24 isi also# welded or otherwise xe'd. to both: the innen andithe. outer cones;

Ine operation of they driery 0f` this invention steam or other heating medium introduced intov the: spacev between the shelr ItIf and outer shell IIIrby rneansof: the inlet pipe I4. and the space between the inletv cones. I2. and. I3; As the outer shell' lil.' contacts the material' to be`V driedv atA portion of'the heating` medium, ese peciallyf steam; willibzercondensed: into liquid; and willy collect. at the lowest point.A between the two shells. As the drier rotatesA (counter-clockwise viewing Figurez2). the; opening I6 passesxinto'th'e condensate.- which flows therethroughinto' the space between the. leading flight" 2 Iy and" the' intermediateznight 26. Continuedf rotation carries the'second opening I 9- intoi the. condensate which flows through itintothe space between the intermediate flight 24` and' tha trailing 'night 232 In themeantimethe condensate. which owed through. thel opening. I8. follows the intermediate iiight. 214.r and: as ther drierrotates' is discharged into the Well 23.1 ini the.y trailingv flight 22.A This condensate -is7 then dischargedthroughtheoutlet pipe:v 20: and is immediately-"followed by: the conidensate` which entered' fronn'the' opening. I 9u. and followed the'trailingflight'zz.

The arrangement otinternal. nights at the dischargey end of they drierof my. invention per# mits1the removal: ofcondensate: from' the-interior ofA thet drier without danger.'l of ilow back and with the. maximumv of eiciency.

In Figure; 3i I'haveshown a. drier according: t'o my invention: in. which. only: an outer shell I0 and: outerinlet. cone: |33 ist used; The outlet end is made: up'in: precisely the?.samaway as in thev embodiment' illustrated. Figures 1 'and'. 2 and: described: above: thisv emloodimentV the condensate: falls directly? to the bottom of the shellf. and? forms af. poot 25" which inl turn feeds through; the openings. Ii and I9v into the/discharge' nights 21,. 212i andi 22?: whichV carry it to the outlet pipe`20..

IrrFigureaA I'havefi'llustrated still anotherem'- bodiment off my: invention. Inl this vform' a'series of horizontal.- pipes 26 or ducts. extend across thev entire? surface` ofthe. interior;A of." the' drier shell.. These pipes` 26. aref fed;v by' ani outer.' I3 and inner. IIII inlet. cone' as; in. the embodiment shown in?k FiguresA 11 andi 2:. The* pipesi dise charge into` a" collector: ring ZI whichA extends around the circumference: of the drum; ati the dischargeend andf collectsz theV condensatefrom they pipes` 26.: This condensate? collects atthe lowest point. ina the: ring: 2x7.' from? which. it flows intothe openings I8 and I9 onto the discharge nights 2l, 24 and 22 which carry itto the discharge pipe 20.

In Figure 5 I have illustrated an embodiment of my invention particularly adapted for vdrying comminuted or finely divided materials such as sand, gravel, cement and ground synthetic resins. In this form an outer cylindrical shell 28`surroundsthe drier and rotates therewith. A series of flanges 29 extend radially inwardly from the interior of the shell 2B and a corresponding series of flanges 30 extend radially outwardly from the surface of the dried. The finely divided material is thus carried around the drier with the rotating drums. The entire drier apparatusis tilted with its axis at an angle to the horizontal so as to discharge the dried material at the lower end.

While I have illustrated and described a present preferred embodiment of the invention and several modifications thereof, it is -to be dis'- tinctly understood that it may be otherwise variously embodied within the scope of the following claims. v

I claim:

1. A rotatable drier comprising a drum having an outer cylindrical drying surface, means for introducing a heated vapor in heat exchange relationship with said drying surface, means inside the drum collecting condensate resulting from i removing the heat from the heated vapor, a pair of spaced-apart'conical surfaces having an annular ring connecting the bases thereof to form a conical chamber therebetween, the outer of said surfaces being connected at its base to the outer cylindrical drying surface, spaced-apart openings in said annular ring communicating with the fluid-collecting means, means beginning adjacent the openings and cooperating with the conical surfaces to carrycondensate along a conical helicoidal path from said openings to' a point on the axis of rotation of the drier and means carrying the condensate from said point to discharge it out of the drier.

2. A rotatable drier comprising an outer cylindrical drying surface, means for introducing a heated vapor in heat exchange relationship with said drying surface, means collecting condensate resulting from removing heat from the heated vapor, a pair of spaced-apart conical surfaces having an annular ring connecting the bases thereof to form a conical chamber therebetween, a pair of spaced-apart openings in said annular ring communicating with the fluid-collecting ring, a conical helicoidal baffle member beginning at a point adjacent to and leading the first of the two openings to enter the condensate when the drum is rotated and terminating at a point adjacent the apex of the cone, a second baffle member including two conical helicoids intersecting intermediate the distance from the base of the conical chamber to the apex to form a water-retaining pocket, said second member beginning at a point spaced from and trailing the last of the openings to enter the condensate and joining the first helicoidal member to enclose within them the apex of the conical chamber and the two openings in the annular ring, an intermediate baiiie beginning at a point between the first and second baflies and terminating at a point adjacent the intersection of the two conical helicoids making up the second baille and means carrying the condensate from the apex of the conical chamber to discharge it out of the drier.

3. A rotatable drier comprising an outer cylindrical drying surface, an inner `cylindrical shell spaced from the outery drying surface and forming 'therewith a chamber, means for introducing heated vapor into the chamber between the vouter drying surface and the inner shell, means'for collecting condensate resulting from removing heat from the heated vapor by the outer drying surface, a pair of spaced-apart conical surfaces having an annular ring connected to the bases thereof to forma conical chamber therebetween, a pair of spaced-,apart openings in said ring communicating between the conical chamber and the chamber between the outer surface and the inner shell, a conical helicoidal baille member begin--A ning at a point adjacent to and leading the first of the two openings to enter the condensate when the drum is rotated and terminating at a point adjacent the apex of the cone, a second baille member including two conical helicoids intersecting intermediate the distancefrom the base of the conical chamber to the apex to form a water-retaining pocket, said second member beginning at a point spaced from and trailing the last of the openings to enter the condensate and joining the first helicoidal member to enclose within them the apex of the conical .chamber and the two openings in the annular ring, an intermediate baffle beginning at a point between the first and second baffles and terminatingat a point adjacent the intersection of the two coni-v cal helicoids making up the second baffle and means carrying the condensate from the apex of the conical chamber to discharge it out of the drier.

4. A rotatable drier comprising an outer cylindrical drying surface, a plurality of parallel axially extending pipes contacting the drying surface, means for introducing heated vaporinto one end of said pipes, means atthe opposite end of said pipes for collecting condensate resulting from removing heat from the heated vapor by the outer drying surface, a pair of spaced-apart conical surfaces having an annular ring connected to the bases thereof to form a conical chamber therebetween, a pair of spaced-apart openings in said ring communicating between the conical chamber and the means for collecting condensate, a conical helicoidal bafiie member beginning at a point adjacent to and leading the first of the two openings to enter the condensate when the drum is rotated and terminating at a point adjacent the apex of the cone, a second baille member including two conical helicoids intersecting intermediate the distance from the base of the conical chamber to the apex to form a water-retaining pocket, said second member beginning at a point spaced from and trailing the last of the openings to enter the condensate and joining the first helicoidal member to enclose within them the apex of the conical chamber and the two openings in the annular ring, an intermediate baille beginning at a point between the first and second baiiies and terminating at a point adjacent the intersection of the two conical helicoids making up the second baille and means carrying the condensate from the apex of the conical chamber to discharge it oui'l of the drier.

5. A rotatable drier comprising an outer cylindrical drying surface, means for introducing heated vapor in heat exchange relationship with said drying surface, means collecting condensate resulting from removing heat from the heated vapor, a pair of spaced-apart conical surfaces having an annular ring connecting the bases thereof to form a conical chamber therebetween,

agneau art-pain' off spaced-apart openings` in said. annular ring. communicating` between the. conical cham.- befz audthe condensate collecting, means apair of connected conical helicoidal baiilesA beginning adiacent said openingsy and. enclosing,r saidi openings andthe apex of. the conical chamber., said helicoids running. in. au. direction counter to. the direction of rotation of. the drier, an inverse curve intermediate, the, ends of the.. conicalheli.- coidcf.' said. pair which. isin .trailingpositionduring, rota-tion. of. said. driersaid.- inverse curve forming a..condensatelgathering, pocket, an inter mediate:semihelicoidalbaia beginning at a point between the. spaced-apart. openings and terminating adjacent the, condensate gathering. pocket to.. dischargev condensate into. said. pocket and means, carrying the condensate from the apex of: the conical` chamber to discharge. it. out. of the: drier..

6'.. A,rotatab1e drier comprising anouter cylindrical, drying, surface. an inner cylindrical shell spaced from the cuter drying surfaceand forming therewitha chamber, means for introducingT heated vapor into the chamber between the outer dryingsurface and the inner shell, a .pair otconnected conical helicoidal4 baliles beginning adjacent. said openings. and enclosing said' openings. and the apex of theconical'. chamber; said helicoidsT nunning in. a direction counter to the direction.. of.' rotation ofv the drier, an inverse curve. intermediate the ends oi` the conical helicoid of' said" pair which is in. trailing position during rotation ofsaid drier, said inverse curve forming a condensate gathering pocket, an inter;- mediate semihelicoidal baffle beginning at apoint between the spaced-apart openings and: termi nating adjacentth'e condensatel gathering pocket to discharge; condensate into said pocket and means carrying' the condensate from the apex of the, conical chamber to. discharge it out of' the drier'.

'1.` A rotatable. drier-` comprising anouter cylindrical drying surface; a plurality, of.A parallel axially extending pipes contacting thedrying'surface ymeans for .introducing heated Vapor" into one end of said'y pipesmeans at the opposite end of' said pipesfor collecting condensate. resulting iii-omv removing heat' from the heated' vapor by the outer drying surface, a pair of spaced-apart conical surfaces having an annular. ringv connect edito the, basesv thereof' to form a. conical'chamber ther ebetween a pair' of spaced-apart.opening s,in said ring communicating between the conical chamber andthe meansfbr collectinglcondensate; a pair of connected conical helicoidal baies'beginning adiacenti said openings and enclosing saidT openings and the apex of' the conical' chamber, saidhelicoids running. in a directionl counter to the direction of rotation ofY the drier, an' in- Verse curveintermediate the ends of the conical helicoid of sai'd'pair which is in trailing position during rotationi of said drier, said. inverse curve forming. a condensate gathering pocket; arr inten mediate semihelicoida'l balei beginning' at a point between the spacedeapart' openings and termi'- nating adjacent the condensate gathering'pocket to discharge condensate into said pocket and means carrying the condensatev from rthe apex of the conical chamber to discharge itjout of the drier'.

GUSTAN" ENGSI'RGM.

References Cited inthe-.filentl this patent,

UNITED STATESPA'L'ENTSP Number Name Date 1,693,934' Millspaughv Dec; 43,1928

FOREIGN PATENTS Number CountryA4 Date 262,77041- Great Britain Dee. f6', 192B 278,882? Great Britain Gct: 202 11927 

